


Back To Brooklyn

by this_wayward_life



Category: Captain America (Movies), Captain America - All Media Types, Marvel Cinematic Universe
Genre: Alpha Natasha Romanov, Alpha Steve Rogers, Alpha/Beta/Omega Dynamics, Alternate Universe - College/University, Anal Fingering, Anal Sex, Beta Clint Barton, Beta Sam Wilson, Blow Jobs, Bottom Bucky Barnes, Courting Rituals, Explicit Sexual Content, M/M, Mating Cycles/In Heat, Minor Clint Barton/Natasha Romanov, Minor Riley/Sam Wilson, Non-Traditional Alpha/Beta/Omega Dynamics, Omega Bucky Barnes, Oral Sex, POV Bucky Barnes, Post-Serum Steve Rogers, Riding, Rimming, Top Steve Rogers, power bottom bucky barnes
Language: English
Status: Completed
Published: 2019-12-08
Updated: 2019-12-28
Packaged: 2021-02-26 00:48:26
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 7,721
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21714823
Author URL: https://archiveofourown.org/users/this_wayward_life/pseuds/this_wayward_life
Summary: Being an Omega sucked. The only thing worse than being an Omega was being a male Omega. And Bucky Barnes had the worst luck in pretty much the entire universe, so it wasn't a big surprise when he presented as an Omega on his sixteenth birthday.So when Bucky's eighteenth came and went, and he finished high school, he wasted no time in moving from his home of ten years in Indiana back to his birth city.
Relationships: James "Bucky" Barnes/Steve Rogers
Comments: 40
Kudos: 818





	1. Chapter 1

**Author's Note:**

> I honestly love A/B/O, and I don't know why it's taken me so long to write one.

Being an Omega sucked. The only thing worse than being an Omega was being a male Omega. And Bucky Barnes had the worst luck in pretty much the entire universe, so it wasn't a big surprise when he presented as an Omega on his sixteenth birthday. His father had looked as if he'd swallowed a lemon, and his mother cried, lamenting about her _poor little boy_ and how he'd _shown so much promise._ Not exactly an ego boost.

So when Bucky's eighteenth came and went, and he finished high school, he wasted no time in moving from his home of ten years in Indiana back to his birth city. Brooklyn, while a bit more hipster-ey than he remembered, was the same acrid smell of smoke and bustle of rude and inconsiderate people that Bucky remembered from his childhood.

Bucky's dorm mate was a mild-mannered Beta called Sam, who cooked dinner every few nights and always told Bucky when he was going to bring his boyfriend Riley over so that Bucky could get out of the dorm before the smell of Betas going at it started permeating the rooms. A few weeks after they met, he and Sam were drunk off their asses, watching CSI Miami and clutching their stomachs from laughter while gorging on Cheez Whizz. While puking his guts out in the toilet while Sam held his hair up wasn't Bucky's proudest moment, it definitely got him a close friend.

The first Alpha Bucky met on the campus who he didn't immediately want to dismember was Natalia Alianovna "call me Natasha" Romanova. Her hair was bright red and artfully curled under her chin, accenting her high cheekbones and green eyes. Female Alphas were almost as rare as male Omegas, and treated just as harshly by society, so as soon as Natalia had seen Brock Rumlow trying to feel him up, she had immediately dislocated both his shoulders, kicked him in the testicles, and appointed herself as Bucky's best friend slash bodyguard. Figuring he had no say in the matter, Bucky idly thought that he could do much worse. 

Along with Natalia came her absolute disaster of a mate. Clint Barton was a Beta that seemed to not understand that pissing off half the city and the mafia was probably not the best idea, and almost always had some kind of injury - usually a broken nose or a black eye. And of course, it fell to Bucky, who was doing a course in nursing, to patch him up - but it was mostly because Natalia would spend the entire time glaring at Clint disapprovingly as she wrapped his ankle, and Sam would chew him out. So Clint always came to Bucky - which was surprisingly not as painful as Bucky had originally thought.

In fact, it was because of Clint that Bucky was hauling his idiot friend up to his dorm in the middle of the night, silently cursing the universe and how heavy Clint was when he was half-unconscious. 

"How did you get into this fight, again?" Bucky muttered, trying not to wheeze.

"Mrphgh," Clint groaned in reply. Well, that was helpful. 

Heaving Clint onto his hip like an oversized baby, Bucky dug around in his friend's pocket for the dorm key, retrieving it with a litany of curses. Eventually, Bucky got the door open and dragged Clint inside, dumping him on the couch and wiping his forehead as he tried to catch his breath. It was then that Bucky heard a choked off sound, making him spin around to try and locate the noise.

Honestly, Bucky was a little disappointed with himself. He was tired, sure, but not tired enough to completely miss the huge blonde Alpha standing in the middle of the kitchenette, holding a glass of water and only wearing a pair of boxers. Bucky was suddenly very aware of the fact that he was in a ratty pair of sweatpants and a tank top, his hair was a complete mess, and he wasn't wearing scent blocker. That last point seemed to be the main reason for the sound that had escaped the Alpha, who immediately clapped a hand over his mouth, looking mortified. His pupils were so dilated that Bucky could see it from here, and a blush had made its way down the Alpha's chest. Bucky pushed down the tiny stir of arousal in his gut.

"I'm guessing you're Clint's new roommate?" Bucky finally said, thanking the gods that his voice was steady. "Stan, right?"

"Steve," the Alpha replied, and _wow_ a voice should not have that much effect on Bucky's hormones. Ignoring the familiar feeling of slick gathering in his hole, Bucky brushed past the Alpha and opened the medicine cabinet, retrieving the rubbing alcohol, gauze and bandages he kept Clint's dorm stocked with.

"If you're gonna be here, make yourself useful and help me patch up my friend," Bucky said as he kneeled down next to the couch, and after a moment, Steve cautiously lowered himself down next to Bucky.

"You do know this is my place, right?" Steve asked, a hint of amusement in his voice. "I don't think you have any authority to be giving me orders."

"Sweetheart, I don't have the authority to do half the things I do," Bucky replied absentmindedly, dabbing at what looked like a stab wound on Clint's bicep. "Now be a dear and wipe the blood off his face. Set his nose while you're at it - you look like you've had plenty of practice doing that."

"Are you saying I have a crooked nose?" Steve asked, sounding like he was trying not to laugh. Bucky finally looked up, an eyebrow raised, and suddenly realised that was a bad idea because Steve was even more attractive up close.

"You also have an uneven collarbone," Bucky replied after a beat. 

"Scoliosis when I was a kid," Steve said, and Bucky nodded as he turned back to make sure his friend wouldn't bleed out. "You have mismatched arms."

If it was anyone else, and if it was said in any other way, Bucky would have punched Steve so hard his nose would be wiped off his face. "Car accident when I was a kid."

Steve didn't offer condolences. Bucky liked that.

"I should get back," Bucky finally said, after a few minutes of working in comfortable silence. Steve smiled crookedly, and held out a hand. Bucky allowed the Alpha to pull him to his feet, and not-so-accidentally stumbled into Steve's chest. The muscles were rock solid under Bucky's palm.

"You could get back," Steve agreed. "But you could always stay here, too." He hadn't let go of Bucky's hand, and his arm snaked around Bucky's waist.

Bucky narrowed his eyes, his mouth curling upwards. "Oh yeah? And do what?"

Steve's eyes were a really nice shade of blue, and as Bucky pressed slightly closer they were almost completely swallowed by black. Steve's voice was hoarse when he replied. "I have a few ideas."

Bucky studied him for a few seconds. "Go all Alpha on me, I'll cut your dick off."

"And what does 'going all Alpha' entail?" Steve asked, his mouth curling into a smile. Bucky couldn't help but smile back.

"Don't hold me down. Don't bond me. Humiliation is off the table. Hit me once and I'll throw you through a wall. And don't forget - I'm the one in charge here."

"I always did like the violent ones," Steve said absentmindedly, his fingers tracing patterns into Bucky's hip. Bucky sunk his nails into the meat of Steve's shoulders and pulled him down for an absolutely filthy kiss, completely ignoring the unconscious Beta on the couch. Steve wasted no timed in reciprocating, hiking Bucky's thigh up and around his waist. Bucky slid a hand into Steve's short hair and pulled, the movement drawing a low growl out of the Alpha. There was nothing gentle about it, nothing soft - it felt dirty, animalistic as if they were stripped to their basest instincts. In some distant part of his mind, Bucky wondered why he felt such a strong connection to Steve, but that thought was quickly pushed away when Steve grabbed Bucky's other leg and lifted him up, not breaking the kiss once. Bucky moaned loudly and tangled his hands in Steve's hair, grinding down onto the prominent bulge digging into his ass. Steve growled and tightened his grip, and Bucky had enough sense left to gasp out, "Bed," into Steve's ear.

Before he knew it, Bucky was being placed down on something soft, much more gently than he was expecting, and Steve was crawling over him to capture his lips once again. Bucky wrapped his legs around Steve's waist again and used the momentum to flip Steve onto his back. Steve looked up at him with barely-concealed shock, and Bucky just grinned and peeled off his tank. When he looked back down, Steve was grinning right back. 

\-----

"What did you do?" Natalia asked as soon as she saw Bucky the next day.

"What makes you think I did anything?" Bucky asked indignantly, ignoring the delicious twinge of pain when he sat down. Natalia raised an eyebrow, unimpressed.

"You're right, let me rephrase that. _Who_ did you do?"

"I'm not a complete whore, Natalia," Bucky grumbled. "Cut me some slack."

"Don't try and play me, James," Natalia warned. "I saw you wince when you sat down. And you smell all fucked out, too."

"How can you smell me? I'm wearing blockers."

"I've had specific training that enables me to ignore scent blockers and scent how people really feel."

"That can't be ethical," Bucky muttered. Natalia just raised an eyebrow. "Okay, fine! I got lucky."

"With an Alpha?"

"How can you tell that, too?"

"You stink of him," Natalia replied matter-of-factly. "I could smell it on you from the other side of the room."

Bucky frowned. "That can't be right. I've had two showers since I've seen him. And I accidentally crashed on Sam's bed. If anything, I should smell like Sam."

"You definitely don't smell like Sam." Natalia wrinkled her nose. "You smell like the art rooms and sandalwood."

"What do I usually smell like?" Bucky asked curiously.

"Burned honey and apples." Natalia raised an eyebrow. "Are you going to see him again?"

"Depends."

"On what?"

"On whether he's home the next time I drag Clint back to his place."

Natalia paused, then her eyebrows raised. "Please don't tell me you had sex with Steve Rogers."

"God, even his name is patriotic," Bucky muttered, avoiding his friend's gaze. "That's honestly the most American name I can think of. Lemme guess - he was born on the fourth of July?"

"He was, actually," Natalia admitted. "But that's beside the point. You slept with Steve."

"I've already admitted this, Talia," Bucky grumbled. "Yes, I slept with him. He ploughed me so hard I can barely walk right now. We both came at least three times."

"Too much information."

"You asked."

Natalia sighed and leaned forward. "James. Steve is a great guy - I should know, I've known him since high school. But he's not exactly the casual sex type. Are you sure you're ready for a relationship?"

"Calm down, Talia," Bucky sighed. "Yes, the sex was amazing, but it was a one-time thing. We were both a bit horny, and I guess he thought I was hot, and we fucked. End of story."

"Mhmm." Natalia sounded unimpressed. "And you'll be totally fine when you inevitably run into him again?"

"Sure," Bucky agreed easily. 

"And you'll also be fine if you don't see him for an extended period of time?"

"We're not bonded," Bucky said petulantly. "We're not dating. I didn't even know his last name until you told me."

Natalia sniffed him again. "Well, you certainly don't smell like yourself. Are you sure you didn't bond? Not even a temporary one?"

"I'm sure," Bucky mumbled. Natalia's eyes narrowed.

"Uh-huh."

\------

Okay, so maybe Bucky did want to see Steve again.

Like, really bad.

It was frustrating. Nobody had ever had such an impact on Bucky before, not even Colin Spencer from Bucky's freshman biology class in high school.

But Steve - Steve was different. He was tall and blonde and exactly Bucky's type. He hadn't minded when Bucky took charge and rode him until they both came, and he seemed to find Bucky hot if the dirty talk was any indication. And if Bucky had stayed just a little while after they'd both finished, and stroked Steve's hair as he fell asleep, then that was no big deal. And he definitely didn't sleep in Sam's bed because the Beta's neutral scent just made it easier to smell Steve on his body. 

And smelling like Steve, even after several showers and body scrubs, was fucking hot. Bucky had never enjoyed smelling like someone else since it always made him feel like property, but Steve's scent was incredible. 

After a few weeks when the feelings of general mushiness didn't go away, Bucky started to get annoyed. This wasn't like him - to fuck someone and then pine after them for weeks after. So he went to a bar, and found an Alpha that smelled like rain and freshly-mown grass, and let the guy slam him into his mattress and rub his scent all over Bucky's body as he fucked him. Bucky left the guy's apartment feeling jittery and dissatisfied. 

Clint was out with Natalia for their weekly date night - meaning Natalia tied Clint to her bed and fucked him to oblivion - but Bucky still found himself knocking on his friend's door. It was relatively late, so Bucky didn't actually expect Steve to open the door, and certainly not looking like _that_.

Because Steve was in nothing but a very tight tank and gym shorts, his hair sticking to his forehead and his biceps glistening with sweat. Bucky could see the outline of his abs from where the tank had stuck to his stomach.

"Bucky? What are you doing here?" Bucky had forgotten to tell Steve his name the last time he was there and only thought of it when Steve was tongue-deep in his ass. Knowing that Steve learned his name during the best rim job of his life made Bucky feel a little hot under the collar.

Without a word, Bucky stepped over the threshold and slammed Steve into the closest wall, kicking the door shut behind them.

"Why can't I stop thinking about you?" he snarled, not giving Steve a chance to respond before he was licking into the Alpha's mouth. God, Steve tasted better than he had last time, and Bucky couldn't help but moan as Steve gripped Bucky by the hair and yanked him closer. Bucky couldn't stop touching - dragging his fingers down Steve's chest, grinding up into his dick, wrapping a leg around Steve's thigh in a desperate attempt to get closer. Steve growled and pushed off the wall, slamming Bucky into it with so much force Bucky swore they put a dent in the plaster.

"You smell like someone else," Steve growled, and buried his face in the curve of Bucky's neck. Bucky cried out when Steve bit down, just inches away from his mating gland, and gouged marks into the Alpha's back. 

"Couldn't get you outta my head," Bucky panted, tilting his head back so Steve could continue ravaging his neck. "Tried to take my mind off you. Just made it worse."

Steve let out a wheeze that sounded like he'd just been punched in the stomach and yanked Bucky up by the thighs with basically no effort whatsoever.

" _Fuck_ you're strong," Bucky gasped, squeezing his thighs around Steve's waist and grinding down, awarding him another choked-off sound. Steve didn't bother with the buttons on Bucky's shirt and instead tore it off him like some kind of caveman, which should not have been such a turn-on.

"Take off your pants," Steve growled, his Alpha timbre making Bucky shudder in delight as he unlatched his legs from Steve's waist and pushed his jeans and soaked-through underwear down. Steve lifted him up again, but much higher, guiding Bucky's legs to his shoulders. Bucky gripped the top of Steve's head as his pelvis was pinned to the wall by Steve's shoulders, and cried out as Steve's mouth enveloped his cock, his nose tucked into the hair at the base, and his finger slid into Bucky's leaking hole.

Bucky had never felt so turned on. He was pinned against the wall, held up completely by Steve's weight, completely at Steve's mercy. Steve had his mouth on Bucky's cock and a finger up Bucky's ass, with Bucky's thighs wrapped around his head so tightly it was probably hard to breathe. Bucky slammed his head into the wall behind him, panting and grinding down on Steve's finger and mouth as hard as he could. Steve slid a second finger inside him and crooked them so perfectly, and Bucky's vision went white as he came down Steve's throat. Steve started to loosen his grip when Bucky finally came down, but Bucky grabbed a fistful of blonde hair and yanked Steve up to look at him.

"We're not done here," he panted. Steve's eyes widened, before he grinned and hauled Bucky off the wall and carried him into the bedroom.

\-----

"I've never felt like this about anyone before," Bucky mumbled sleepily, his face pressed into one of Steve's pecs. Steve hummed, and Bucky could feel the vibrations under his cheek as a large hand stroked down his back.

"Well, I am pretty amazing," Steve murmured, and laughed quietly when Bucky whacked his arm. "Me neither, sweetheart."

"At first I thought maybe we bonded, by accident," Bucky went on, and started to trace patterns in the blonde hair on Steve's chest. "But I don't think so."

"Maybe we're compatible," Steve suggested. His voice was slightly muffled from when he'd buried his face in Bucky's hair. "We're exhibiting symptoms of a highly compatible pair."

"What have I said about scientific pillow talk?" Bucky whacked Steve's bicep again, earning another chuckle. "And besides, compatible pairs are almost non-existent."

"Keyword is 'almost'," Steve mumbled, gathering Bucky tighter in his arms. "Now shut up. I wanna go to sleep and you're a great cuddle buddy when you shut your trap."

"Is that what we are now? Cuddle buddies?"

Steve tilted his head down and met Bucky's eyes, a sleepy smile on his face. "We can be whatever you want us to be, sweetheart."

"And what do you want us to be?" Bucky asked softly, not even attempting to hide the sappy grin on his face. Steve hummed and nuzzled Bucky's cheek.

"Boyfriends sounds nice, for now."

Bucky leaned up to kiss him softly. "As long as you cook breakfast in the morning."

Steve just smiled and kissed him again.


	2. Chapter 2

**Summary for the Chapter:**

> It started when Bucky left the next morning.
> 
> \-----
> 
> Steve and Bucky realise some of the struggles of being a compatible pair.

**Notes for the Chapter:**

> Oof I knew this felt unfinished. Have another chapter that has literally no plot and is mainly sex.

It started when Bucky left the next morning, messy hair tied in a bun and wearing one of Steve's shirts. Steve had cooked him breakfast and kissed him breathless before Bucky left half an hour later than he meant to, getting into his morning lecture ten minutes late. He couldn't focus on anything, his leg wouldn't stop bouncing, and there was an undercurrent of anxiety that just wouldn't go away. 

Silently thanking some greater power he didn't believe in that he only had the one class that day, Bucky didn't even stop for a coffee on his way back to the dorm. Every Alpha he passed on the street seemed like a threat, every Omega a rival. Even the Betas seemed suspicious. When Bucky closed the door to his dorm with probably more force than was necessary, he couldn't help the relieved sigh that caused him to sag against the door. Through a haze, he didn't notice Sam and Riley at the table five feet away.

"Dude. You okay?" Riley finally said, and Bucky jumped and spun around to look at them. Both wore matching concerned expressions and looked like they'd just got out of bed. Unlike the Betas on the street, their scent made Bucky relax enough to turn his back on them as he toed off his shoes.

"I'm fine."

"Uh-huh," Sam drawled, raising an eyebrow. "Then why do you smell like that?"

"Smell like what?" Bucky asked vaguely, moving past them into the kitchenette. God, he needed a coffee.

"Like an Alpha I've never met, anxiety, and..." Sam sniffed the air. "Preheat?"

"My heat's not due for another month," Bucky said, grabbing his favourite mug from the cupboard and dumping far too much instant coffee into it.

"Bucky, who's the Alpha?" Riley asked, worry evident in his voice. "Did they do anything you didn't want?"

"No! Steve would never-" Bucky cut himself off, feeling his face start to heat up. "I mean... no. Nothing happened that wasn't consensual."

"Steve, huh?" Now that Bucky had reassured them that he hadn't been hurt, he could hear Sam's sly tone. "Wanna tell us about him?"

"Nope," Bucky said quickly, and carried his coffee into his room as fast as possible. "Bye, Sam. Nice to see you, Riley!"

"Bye, Bucky," Riley called, because he was nice.

"My little baby's all grown up," Sam called tearfully after Bucky, because he was an asshole and didn't deserve friendship. Bucky slammed the door behind him.

Then immediately walked back out. "Alright, I'm not okay."

Sam immediately went from asshole to concerned friend, and Riley's eyes somehow got wider and more worried. Jesus, the guy could give a puppy a run for its money.

"Is it about the Alpha?" Sam asked gently. Bucky sighed heavily and sat down opposite Sam and Riley, running a hand through his hair. 

"Yes. No. I-" Bucky cut himself off and growled in frustration. There was a tugging in his stomach and a persistent thrum of an oncoming panic attack. "I don't know."

Riley leaned forward slightly. "Bucky, what do you feel right now?"

Bucky looked at him oddly. "Why do you want to know?"

"Just a hunch," Riley replied, the focused look not leaving his face. 

Bucky hesitated for a second. On the one hand, he rarely showed weakness around other people, if ever, and emotions certainly fell into that category. But Riley and Sam were his _friends_. If he couldn't trust them, he couldn't trust anyone. And considering that Riley's major was designation and gender studies, and Sam's was psychology, they would be Bucky's best bet in figuring out what was going on between him and Steve.

"It was supposed to be just sex," Bucky finally blurted out. "We spent one night together. I didn't even stay afterwards. Natalia could smell him on me, even though I took two showers and slept in your bed after, Sam."

"So that was why your bed smelled like Bucky," Riley mumbled, and Sam went bright red. Bucky ignored them.

"But I couldn't stop thinking about him. It was constant - like this itch that I couldn't scratch. And after a few weeks it just got to be too much and last night I went over and we fucked again."

"Did you talk?" Sam asked, raising an eyebrow.

" _Yes_ , Sam, we did talk," Bucky said primly. "I thought we accidentally bonded, he thought we might be compatible. And when I left I started feeling anxious and paranoid."

"What do you mean by that?" Sam asked. 

"I can't stay still," Bucky admitted. "I need to know everything that's going on around me. I'm constantly on the edge of a panic attack. I couldn't concentrate on my lecture, and when I was walking home I felt like everyone was out to get me."

"Do you miss Steve?" Riley asked suddenly. Bucky blinked, and then it all hit him at once.

He _did_ miss Steve. He missed Steve far too much. It felt like he'd known Steve for years, and been away from him for months, and Steve was finally in his sights but just out of reach. It was so much, too much. Bucky looked at Riley for a second and burst into tears.

Riley immediately gathered Bucky up in his arms and led him over to the couch, cooing soothingly and sending out calming pheromones. Bucky clung to him like a newborn clinging to its mother, only letting go to accept the steaming mug that Sam pressed gently into his hands.

Bucky hadn't cried since just after he left home. He'd been on a train at two in the morning, travelling to Brooklyn, when the stress and anger and fear finally boiled over and he'd collapsed against the window and sobbed, letting the despair and self-hatred wash over him like a malevolent blanket, wrapping him up and cutting him off from the outside world. A kind old Omega had calmed him down by rubbing his shoulders and crooning softly, and then giving him a pat on the cheek when he'd thanked her and apologised for breaking down.

While neither Sam or Riley could give him the safe feeling that an older, maternal Omega could, Bucky was closer to them and felt no shame in snuggling close to Riley and breathing him in deeply, letting out the breath with a shudder as Sam rubbed his back gently. Thankfully, the breakdown didn't last long, and Bucky regained control of his emotions after a few minutes of pathetic sobbing, leaving him feeling drained and tired out.

"I don't know what's wrong with me," Bucky mumbled into Riley's chest, taking a small sip from the mug Sam brought him. The drink was warm and milky, with a hint of cinnamon and some other spices that Bucky couldn't name.

"I have a few theories," Riley murmured, running his hand through Bucky's hair. Bucky melted into it and purred gently. "It's probably a combination. I'm guessing you and this Alpha are compatible, and accidentally formed a temporary bond as a result. And that bond grows stronger every time you're together sexually, which is why you're feeling so awful right after you slept with him."

"How do I make it stop?" Bucky asked wearily.

"Apart from seeing your Alpha, I don't think there is anything," Riley said guiltily. 

"You could be True Mates," Sam mused. "It's incredibly rare, but there have been reported cases of pairs who were so compatible that science had to create a whole new category to put them in. But it's usually in Beta pairs."

"This is so confusing," Bucky mumbled.

"You'll feel better after a nap," Riley said gently.

"It's barely eleven," Bucky protested, but allowed Sam and Riley to pull him to his feet and guide him into his bedroom.

"And you don't have anything on today," Sam said, brushing Bucky's hair out of his face in a gesture that was achingly paternal. "Just sleep. Riley and I will be here when you wake up."

Bucky couldn't think of another protest, so he crawled into bed and allowed Riley to tuck him in. He was asleep in minutes.

\------

Bucky woke not two hours later to the sound of voices outside his room. He recognised Sam and Riley's voices, but then someone laughed who was definitely neither of his friends. Pulling himself out of bed, Bucky quickly swapped his pants for some clean ones (he couldn't bear taking off Steve's shirt) and ran a hand through his hair in an attempt to stop it from sticking up (a fruitless task), before walking out into the main room.

Sam was in the kitchen, his body turned towards Bucky, with Riley next to him stirring a pot. A man with large shoulders sat on one of the stools with his back to Bucky. Very familiar shoulders. When Sam smiled at Bucky, the man turned around, and his scent hit Bucky with the force of a truck.

"Hey, you're up," Sam said cheerfully. "Bucky, this is my friend Steve-"

Sam had barely finished his sentence before Steve was out of his chair and halfway across the room, Bucky almost running to meet him and flinging himself into the Alpha's arms. Steve's arms were like tree trunks as they wrapped around him, thick and corded and so warm, and Bucky pressed himself as close as possible to Steve's body, nuzzling into his neck with a small sound. Steve whined and shoved his face into Bucky's neck, scenting and kissing. His lips were so soft, and his hair tickled Bucky's cheek, and Bucky felt like he was floating in pure bliss, wrapped up in the arms of a big, strong Alpha who could protect him, who would dote on him and spoil him rotten, because that's what Steve did, he looked after Bucky, and he did it _so well_...

"I'm guessing you two have already met." Sam's dry voice cut through the almost orgasmic bliss Bucky was feeling, and he felt Steve lift his head to growl threateningly at the competition. "Bucky, you didn't tell me your Steve was Steve Rogers."

Bucky didn't bother answering, and instead pressed an open-mouthed kiss to Steve's pulse point. The Alpha melted back into Bucky's embrace, cooing happily and lifting Bucky's shirt to rub his wrists on his back. 

"Okay, Sam and I are going to leave for a few hours, buy some scent diffusers, and then we're all going to sit down and talk," Riley said, but Bucky barely heard him, because Steve's hands had migrated to his ass, rubbing and kneading the soft flesh through the fabric of his sweatpants. Bucky whined and pressed his hips forward, leaning back into Steve's neck for another smell. God, Steve smelled so good. Bucky didn't want to ever let him go; Steve would just have to go about his life with a Bucky-shaped lump clinging to him like a koala. 

"Yeah, we're definitely leaving," Sam said loudly, and after a few seconds Bucky heard the front door slam, and the only thing that existed was Steve, and him and Steve together. Steve's hands gripped the back of Bucky's thighs and lifted, holding all his weight up like it was nothing. Bucky, having lost most of his higher brain function, could only wrap his legs around Steve's waist and bury his nose in Steve's neck as he was carried away and laid down somewhere soft and warm. 

Steve's arms started retreating, and Bucky cried out and grabbed his forearms, pulling him back down so his body blanketed Bucky's. Steve let out a low rumble and pressed kisses all over Bucky's face, and Bucky melted into it enough that he didn't process Steve's attempts at retreat until the Alpha was leaving the room, Bucky's arms still outstretched. Before Bucky could react (read: start crying), Steve was back, his arms laden with pillows and blankets from the linen closet that Sam always kept so tidy. 

Bucky's eyes widened as Steve started bunching the pillows up around the headboard and on the side of the bed in a nest, creating soft walls that cocooned Bucky in. Steve, pausing in his nest-making efforts, wrapped his arms back around Bucky and lifted him off the bed, laying down more blankets before he deemed it satisfactory. Bucky curled into him, the stinging rejection he felt when Steve left ebbing away until all he could feel was contentedness. Steve kept up that low hum, and it washed over Bucky and left him feeling weightless and blissed out. He barely noticed when Steve started tugging off both their clothes until he laid Bucky in the nest and pulled him close, his bare skin soft and warm and perfect. Bucky tucked his head into the crook of Steve's neck again and breathed in deeply, the now-familiar scent of sandalwood and paint leaving his head spinning and chest bursting with happiness. Steve's humming was a constant comfort, the steady tone and monotonous nature making Bucky's eyelids heavy. He was warm, he was comfortable, he was in the nest his Alpha made, and it was more than enough to send Bucky drifting off to sleep.

\--------

Bucky was warm. Wherever he was felt soft and warm and perfect, and there were large arms wrapped around him, holding him close. Someone was breathing softly on his neck, and there was a beautiful smell in the air that made Bucky's body release a wave of slick. A large cock pressed into the cleft of his ass, hips rolling in a steady rhythm, and Bucky pressed back against it, panting. 

The person behind him - the _Alpha_ behind him - hummed low in his throat, his cock nudging against Bucky's hole, and Bucky whined softly, leaning his head back against the Alpha's shoulder. A large hand trailed down Bucky's stomach and wrapped around his cock, easily covering the whole thing. Bucky lifted his leg and ground his ass back against Steve's cock, and the head slowly slipped into his hole, aided by the slick that was almost dripping out of him. 

The Alpha's mouth latched onto Bucky's neck, suckling gently as he slowly slid further inside. He held Bucky's cock gently and slid his thumb up and down the shaft, his other hand sliding around Bucky's chest to rub his nipples. Bucky arched his back and moaned quietly as Steve bottomed out, surrendering himself to the pleasure that surrounded him. The Alpha kept making soft noises as he started to slowly roll his hips, not letting an inch of his cock leave Bucky's hole. It wasn't very fast or rough, but the torturous roll of Steve's hips, the soft callouses on his hands, and his hot, wet tongue moving against Bucky's scent glands was the hottest thing he'd ever experienced. Bucky reached back to thread a hand through his Alpha's hair - and it was _his_ Alpha, because they were in their nest and Steve had Bucky's scent rubbed all over him and his cock was deep in Bucky's ass - and turned his head, drawing him into a kiss. The Alpha's lips were so soft against his, the faint hint of stubble providing perfect friction against Bucky's face. 

"Alpha," Bucky whispered, and Steve growled softly.

"My Omega," he murmured, catching Bucky's lips in another kiss. "Mine."

Another roll of his hips left Bucky seeing stars, and he arched upwards and cried out, his nerves singing. Steve's hand on his cock moved a bit faster, his hips snapping upwards a little rougher, and Bucky's hands scrabbled for purchase on the soft sheets and firm muscles surrounding him. 

"Alpha, Alpha please," Bucky begged, grinding his hips back against the cock that was splitting him open. Steve moaned softly and bit down, right next to Bucky's mating gland, and the base of his cock started swelling. Steve's thrusts got faster and more erratic, and Bucky eagerly ground back against him, taking his cock to the hilt. It wasn't long before his Alpha's knot caught on Bucky's rim, and a hot jet of come flooded Bucky's insides, making him cry out in ecstasy. Steve was whimpering and moaning into the back of his neck, thrusting as much as he could, and it wasn't long before Bucky followed him over the edge, his vision turning white.

Bucky must have passed out, because when he opened his eyes again his Alpha had already wiped him down, and was cooing softly into his ear, rubbing their scent glands together. Bucky purred softly and melted back into him, the cock inside him making him feel comfortable full.

"My Bucky, my sweet Omega," Steve purred softly, and Bucky hummed, reaching back to run his fingers through his Alpha's hair. 

It took a while for the post-sex haze to lift, enough time that Steve's knot had deflated but was still inside him, but when it did Bucky turned his head to look at him. 

"You're really pretty," Bucky mumbled. And he was - the soft blonde hair, blue eyes and fair skin, with those crinkles around his eyes and full lips, his Alpha was perfect. Bucky stared into fond, blue eyes, and felt his mouth twist up in a smile. "Kiss me, Stevie."

Steve closed the small distance between their lips to kiss Bucky softly, gathering up the Omega in a tighter grip. The kiss was chaste and sweet, and Bucky turned around in Steve's arms - whining softly when the soft cock slipped out of him - to wrap his arms around Steve's neck, keeping him close. Steve purred happily, and Bucky couldn't help but giggle, breaking the kiss to bury his face in Steve's neck. Steve held him tightly, his body shaking with laughter of his own.

Their little bubble was promptly burst by a loud knock at the bedroom door. 

"Rogers! Barnes! Get your horny asses out here!" Sam bellowed through the door. "You promised me a talk, we're gonna talk!"

Bucky grumbled and mashed his face into Steve's pec, causing his Alpha to laugh again and kiss the crown of his head. They did eventually get out of bed, pulling their clothes off the floor and catching each other's eye and giggling, barely able to keep their hands off each other. It was exhilarating. 

When they finally opened the door, Bucky saw Sam and Riley sitting on the couch, a bunch of scent diffusers on the coffee table. Riley looked amused, whereas Sam looked disgusted.

"You're awful. I hate both of you," he said immediately. "You stink, you're horrible, you shouldn't be allowed happiness."

Riley rolled his eyes. "Babe, can you plug in those diffusers? Especially in Bucky's bedroom?"

Sam looked at him in horror. "I'm not going in there."

"Then you can let the whole apartment stink," Riley replied casually, which made Sam fly out of his chair and grab all the scent diffusers he could. Riley then turned to look at Steve and Bucky curiously. "Okay, what do you guys remember?"

Steve frowned, and his brow furrowed so adorably Bucky couldn't help but reach up to try and smooth it out. Steve immediately turned his attention to Bucky, his eyes going soft and a smile curling his lips and Bucky leaned up to kiss him softly.

"Guys," Riley said, and they broke apart. Bucky shook his head slightly, a fog in his mind. "The last thing you remember?"

"I came back here after my lecture and went to bed," Bucky said, leaning on Steve. 

"Sam and I had made plans to catch up, so I went over to his dorm to pick him up and ended up coming inside," Steve said distractedly. His hand was rubbing circles on Bucky's hip, and it was really distracting.

"You made me a nest," Bucky sighed, kissing Steve's neck, and Steve wiggled happily, leaning down to mouth at Bucky's mating gland. 

"This is so weird," Riley said, his voice sounding very far away. "You guys are sending each other into heat and rut. I've never seen anything like it."

Bucky ignored him because Steve's hands were sliding down his ass to his thighs, and then he was being lifted into Steve's lap. Bucky could feel Steve's hard cock pressing into his ass, and ground down on it as he pulled Steve up for a kiss. Steve whined, and one of his hands slipped below the waistband of Bucky's sweatpants, rubbing at his hole. Bucky was vaguely aware of other people in the room, but Steve's finger slowly slid into him and it didn't matter. In the back of his mind, Bucky heard a door open and close, but he was too caught up in Steve's touch and the smell that was permeating the air. It was slightly tangy, with an underlying sweetness, and Bucky moaned when he realised it was the smell of rut. Steve groaned too and stood up, holding Bucky by the thigh with one hand, the other hand still down the back of Bucky's pants.

"Take me to our nest," Bucky breathed, and his Alpha whined and started moving towards their nest. Bucky was laid down gently, and Steve almost ripped his clothes off in his eagerness. Bucky rolled onto his stomach, got his knees underneath him, and arched his back, spreading his legs and presenting. Steve growled and got into the nest behind him, his thick hands running up Bucky's naked thighs, rubbing the slick that had dribbled down from his hole. Bucky pushed back against him, whining softly, and Steve cooed gently, still rubbing his skin. Then there was something hot and wet touching Bucky's hole and he jumped, yelping in pleasure as he was breached by Steve's tongue. 

"Alpha, Alpha," Bucky chanted, his skin starting to heat up. The nest was so warm, and Steve was warmer, and Bucky was burning, surrounded by heat and love and with Steve's tongue and fingers so deep inside him. Bucky was floating on the precipice of his world and another, and all he could think of was Steve, and Steve's touch, and Steve's cock pressing slowly into his hole, and the explosion of heat and pleasure as he made that leap and the world exploded into colours.

\------

As far as Bucky could tell, his and Steve's joint cycles lasted eight days. A normal cycle would last half that time, and by the end, Bucky was sore and exhausted and absolutely starved. Between the two of them, he and Steve devoured two family-sized pizzas each, and several gallons of water. Sam and Riley had called Natasha, Clint and two dudes called Tony and Bruce over, and all six of them watched with horrified fascination. As he and Steve were eating, Sam and Riley explained the situation, with mixed reactions. Clint started crying and babbling about 'true love', Natasha glared at Steve as if everything was his fault, Tony looked both disgusted and fascinated, and Bruce's eyes were wider than saucers.

"They're True Mates," Bruce said immediately.

"Wha' dos tha' mean?" Steve asked through a mouthful of pizza, and Sam shot him a disgusted look.

"It means that you two are over 80% compatible, which is next to unheard of, especially for Alpha/Omega pairs. I'm guessing that you felt a strong attraction towards each other when you first met and that only increased every time you slept together until it grew to be so much that it triggered both of your cycles."

"A heat that lasted eight days?" Tony said in horror, looking at Bucky with both sympathy and awe. "How chafed _are_ you?"

"So what, it's only biological?" Bucky asked, and next to him, Steve's scent went sour with distress. 

"These kinds of things physically _cannot_ happen if you two aren't attracted to each other in a non-physical way, or have the potential to," Bruce said. "So either you two are already in love, or you're on your way to falling in love. True Mates are really rare, like I said, so we don't have that much information on them, but about 70% of the attraction has nothing to do with designations or hormones."

"So what do we do now?" Steve asked, finally putting his pizza down. Bruce shrugged.

"I would highly advise against breaking up at this time," he said. "That would send your cycles out of wack again, and your bodies would treat it like the breaking of a bond. Once your hormones calm down a bit, if you want to separate, that wouldn't be a problem. Other than that, do whatever you want."

Steve looked thoughtful, and Bucky couldn't help the bubble of foreboding slowly growing bigger in his chest. It was almost the size of a baseball by the time everyone left, Sam loudly proclaiming that he'd stay at Riley's.

"So," Bucky said finally, forcing himself to keep his voice light. "You still wanna court me?"

Steve huffed out a laugh and leaned back into the couch. "What kind of question is that?"

"Well, you did ask me to be your boyfriend. I'd totally understand if you didn't want that anymore." 

Steve looked over at him in shock. "Bucky, that is the last thing I want to do. And anyway, you heard what Bruce said about not seeing each other - it'd ruin our lives, maybe permanently."

"So you'd just be staying with me for the sex? For convenience?" Bucky didn't know why he was pushing the issue, but he couldn't seem to stop. Steve looked even more horrified.

"Baby, of course not!" Steve scrambled off the couch to kneel between Bucky's legs, cupping his face in his hands. "Bucky, there's nothing that I want more to court you. I want to take you out on dates, and find out what kind of flowers you like so I can buy them, and learn about your life and your family, and I want to make love to you and pamper you, because you deserve the entire world."

"And what about what Bruce said?" Bucky asked, and his voice was a lot smaller than he'd meant it to be. "Will you break up with me as soon as you can?"

"No," Steve said emphatically. "I know that we haven't known each other very long, but I know now that I want to spend the rest of my life with you, Bucky Barnes."

Bucky felt tears well up in his eyes, and he couldn't help but throw his arms around Steve's neck and kiss him, pouring as much love as he could into it. Steve's arms went around his waist and crushed him close, and Bucky had never felt so safe, so cared for, so _loved_.

"I love you," Bucky gasped out between kisses. "I know it's too soon, but I love you so much."

Steve whined and licked into Bucky's mouth, drawing out whines and moans. "I love you too sweetheart, _God_ I love you."�  
Bucky sobbed and gripped Steve tighter, letting himself forget everything that wasn't Steve. And as he calmed down and tears stopped forming, Steve rubbed his back and cooed softly in his ear, making Bucky relax until he was a puddle of goo.

Bucky barely noticed as Steve picked him up and carried him into the bathroom, holding him close to his chest as the hot shower water poured over them. Steve's hands were rubbing gentle circles on his hips, and Bucky leaned close to his Alpha, allowing him to wash and dry him. They didn't bother with clothes and crawled into the newly-made bed, two scent diffusers plugged into the wall beside them. Bucky fell asleep like that, curled against his Alpha's chest, finally content.

**Notes for the Chapter:**

> Wow I love A/B/O. Hope you enjoyed!

**Author's Note:**

> This feels a little unfinished to me, but I didn't know what else to do with it, so here you go. Hope you enjoyed!


End file.
